The Environmental Working Group (EWG) on Wednesday launched its drinking water database, which allows anyone in the U.S. to enter a zip code and find out which contaminants can be found in local water supplies.

Additionally, the Washington, D.C.-based nonprofit organization tracks the levels of contaminants found in local water sources. It also reports if those levels are above the legal limits set by the EPA, or if they're found in amounts that scientists believe are dangerous to human health.

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This is the third update to the nationwide database, the only one of its kind, according to EWG.

Nneka Leiba, the leader of the project and director of EWG’s Healthy Living Science Program, said it took researchers two years to collect 30 million test results from 50,000 utilities across 50 states. Leiba said some of the results were alarming.

The EWG identified 267 different pollutants in data from U.S. water utilities. Leiba said 93 were linked to cancer, 58 were associated with brain and nervous system damage, and 38 were linked to fertility problems.

About 80 percent of drinking water in the U.S. is considered surface water, which is found in rivers, lakes, reservoirs, streams and creeks.

“Most surface water systems tend to have a lot more pollution from agricultural and industrial runoff or urban activity," explains Leiba. "Some of the processes used to treat water can also create harmful by-products. A lot of the industrial facilities have outlets or other ways of disposing their effluents that can end up in our streams. With agriculture, it’s the same thing – a lot of waste ends up in streams, which are the drinking water sources for millions of Americans.”

Even more disturbing, Leiba said, is that more than 50 percent of chemicals found in U.S. drinking water don't have legal limits, which means they can be present at any level.

"The legal level isn’t necessary a safe level, it's a compromise between safety and how easy and costly it is to remove a chemical from water. Legal doesn’t mean safe," says Leiba.

An EPA spokesperson released the following statement about the report:

"America’s drinking water remains among the safest in the world and protecting drinking water is one of EPA’s top priorities. We take our commitment to protecting public health seriously and when issues arise, we work closely with states, local governments, and water suppliers to review and address, as appropriate."

Those concerned with tap water safety can contact their supplier for more information, the EPA says. They can also request a copy of their local Consumer Confidence Report, which lists levels of contaminants detected in water sources - and if they meet state and EPA regulations.

The EWG recommends reaching out to elected community officials and urging them to support source water protection programs.

"For the most part utilities are doing the best they can to purify and treat the water that comes into their system," Leiba says. "But surface waters are becoming more polluted as we use more chemicals in this country. We need better infrastructure and more resources to upgrade facilities and treatment processes."